In order to extend the reliability of tracking capabilities of resources such as consumables of laboratory devices, optically readable identifiers (such as barcodes or QR-codes) are being replaced or complemented by identifiers readable by the use of radio-frequency electromagnetic fields. Particularly common are radio frequency identification RFID tags enabling wireless, non-contact automatic identification and data capture.
While RFID tags provide major advantages over optically readable identifiers, such as no need for direct line of sight between identifier and reader, RFID technology also introduces certain disadvantages/difficulties. One such disadvantage is a consequence of the fact that an RFID reader antenna can communicate at the same time with all RFID tags within its range, and thus their individual identification/localization is not as straight-forward as for optically readable identifiers. In some scenarios such as inventory operations this aspect might not be problematic as only the presence/absence of an RFID tag is to be determined.
However, in many occasions it is very important that the correct identifier is addressed, such as when the exact location of an object or its relative location to an RFID reader antenna is to be identified. One particular field is the use of RFID tags to identify resources such as consumables of laboratory devices having multiple RFID reader antennae at loading/holding/processing positions (such as rack positions) of the resources. Since these loading/holding/processing positions of the resources are commonly located in relatively close proximity with respect to each other, addressing of an RFID of a neighboring position to the one where the particular RFID reader antenna is located is a common concern. One known approach to address this issue is for an RFID reader antenna to address all RFID tags in its vicinity and identify the RFID tag providing the strongest return signal as the tag located in the immediate proximity of the RFID reader antenna.
However, experience has shown that this approach often provides unsatisfactory results, i.e., in some occasions the wrong resource is identified to be present in a particular loading/holding/processing position. The consequences of two different consumables such as two different reagents being wrongly identified as being in a particular location in a laboratory device are extremely severe, such a mix-up having the potential to invalidate an entire batch of analysis, or even if the mix-up is not recognized, false results are reported by the laboratory device.
Embodiments of the disclosed method and device therefore aim to provide improved association of RFID tags to RFID reader antenna in a laboratory device, and in particular, to correctly identify resources of laboratory devices with their respective loading/holding/processing positions.